Improving impedance matching of flaky carbonyl iron based on the surface modification by binary coupling agents

Huimin Wu,Ningyan Xie,Yan Zhu,Guozhi Xie,Jing Chen

doi:10.1007/s10854-021-06175-z

Abstract

In this paper, the impedance matching of the flaky carbonyl iron was improved by surface modification with binary coupling agents. The microstructure, phase and electromagnetic parameters were detected by Scanning electron microscope (SEM), X-ray diffraction (XRD) and Agilent vector network analyzer, respectively. After binary coupling agent applied, the shape and particle size of the flaky carbonyl iron particle (CIP) have changed significantly, whereas the phase remained \({\alpha }\)-Fe phase. On the other hand, with the addition of binary coupling agents, the complex permittivity of flaky CIP is reduced, which is beneficial to impedance matching. The doping with 2wt% calcium stearate and 2 ml titanate to flaky CIP has a minimum reflection loss peak of − 13 dB at the thickness of 2 mm. It is noted that the effective absorption bandwidth (RL < -10 dB) is up to 0.8 GHz (1.8 ~ 2.6 GHz). Moreover, the magnetic tangent loss of the samples can be significantly improved by the addition of binary coupling agents. Therefore, the surface modification of binary coupling agent can make flaky CIP get better impedance matching and absorbing performance in S band.

Highlights

Many efforts have been made to reduce the excessively high dielectric of flake carbonyl iron, such as flake carbonyl iron/Fe3O4 composite (CI/ferrites composites) [1], core-shell structure flaked carbonyl iron powder@SiO2 nanocomposite [5], flake carbonyl iron combined carbon-based material [12], chemical modification [13]
The modification of binary coupling agents can improve the microstructure of flaky carbonyl iron particle (CIP) more effectively
The results indicate that the addition of binary coupling agents can effectively improve impedance match and absorption properties for flake CIP in this study

Summary

Introduction

Many efforts have been made to reduce the excessively high dielectric of flake carbonyl iron, such as flake carbonyl iron/Fe3O4 composite (CI/ferrites composites) [1], core-shell structure flaked carbonyl iron powder@SiO2 nanocomposite [5], flake carbonyl iron combined carbon-based material (carbon nanotubes/carbonyl iron powders complex absorbents) [12], chemical modification [13]. Based on our previous research [19], the role of binary coupling agent modification on the microstructure and microwave absorbing properties in S band of flake CIP are studied in this paper. The flaky CIP was obtained from raw spherical carbonyl iron powder (SCIP) (Co. tianyi, Jiangsu, China) by ball milling method. It has been mentioned in our pervious study [20]. Calcium stearate and Titanate (DN-101) were selected as the Surface modification during milling process. The wet milled slurry was dried in a vacuum (DZF-6020 Co. suoyu, shanghai, China) oven at 60°C for 6h, the desired surface modified flaky CIP samples were obtained.

Methods

Results

Conclusion